ROLLING MEADOWS, IL (June 23, 2005)…The Institute of Environmental Sciences and Technology (IEST) has issued Contamination Control Recommended Practice IEST-RP-CC034.2, HEPA and ULPA Filter Leak Tests. Leak testing high-efficiency particulate air (HEPA) filters and ultralow-penetration air (ULPA) filters is an important part of verifying filter performance. This newly expanded Recommended Practice (RP) covers definitions, equipment, and procedures for leak testing HEPA and ULPA filters in the factory as they are produced, at the job site before they are installed, and after they are installed in cleanrooms and in unidirectional-flow, clean-air devices. The RP also includes procedures for measuring the uniformity of the aerosol challenge approaching the filter under test.

The choice of which test procedure to use depends on the performance level of the filters, clean-air device, or cleanroom, and on the intended application. Section 5 of the RP provides guidance for selecting the appropriate leak-test method. The 44-page document goes on to describe recommended test procedures, including two methods for scanning the downstream surface of the filter and one method for determining if there are leaks in inaccessible filters.